Every three years, the Minnesota Pollution Control Agency (MPCA) submits a list of impaired waters to the U.S. Environmental Protection Agency (EPA). A waterbody is considered impaired if a pollutant is found in the water at a level that exceeds state standards. When a waterbody is declared impaired, the state must take steps to remove the impairment, which includes creating a Total Maximum Daily Load (TMDL) plan. Wastewater facilities that discharge into an impaired waterbody may find that new limitations are placed in their permit to help address the impairment.

Last week, EPA informed MPCA that it was adding 30 additional waterbodies to its impaired waters list because they exceed Minnesota’s sulfate water quality standard. This standard has been the source of much controversy because it is based on what many experts describe as inaccurate and outdated research. MPCA attempted to revise the standards several years ago, but the proposed rule was rejected by an administrative law judge.

Adding these 30 waterbodies to the impaired waters list could impact several Greater Minnesota cities because it could lead to sulfate limitations in their wastewater permits. Right now, removing sulfate from wastewater is not economically or technologically feasible. The main process to remove this pollutant is reverse osmosis, but it is prohibitively expensive at the wastewater level. The resulting sludge from the process is also expensive to remove.

EPA opened a public comment period that began April 29 and closes May 31. You can read more about EPA’s decision and the public comment period here. Further questions may be directed to MESERB attorney Gretel Lee at gllee@flaherty-hood.com.